This invention relates to an apparatus for dispensing and applying dental materials. In particular, the invention is directed to a device for effecting ejection of an extrudable dental material such as gutta percha into a root canal, and to cartridges for holding and heating dental materials in connection with said device.
Endodonic dispensers such as are known and disclosed in the art are manually actuated. These manually operated devices require one hand to squeeze a lever or press a plunger while the other hand is used to manipulate the device for positioning the probe. With these cumbersome devices, it is very difficult to accurately and precisely position the probe. It is accordingly a purpose of the present invention to provide a power driven dispenser so that manual operation is not required. Hence, both hands can be used to guide and to direct the applicator into the best possible position for accomplishing the intended purpose and with the least danger or discomfort to the patient. It is a further purpose of the present invention to provide a device which is relatively simple to manufacture and maintain. It is also a purpose of this invention to provide a disposable cartridge for dental materials to be used with the automatic dispensing device of this invention.
U.S. Pat. No. 3,900,954 to Dragan discloses a dental filling gun with a manually operated plunger. The dental filling gun includes a detachable plastic nozzle tip which defines a reservoir for containing a predetermined amount of dental filling material. U.S. Pat. No. 4,265,618 to Herskovitz et al. discloses an endodontic syringe that contains an electrical heating section in the syringe barrel. Heated thermoplastic material is ejected through a hollow needle. The needle is made from a material having a high coefficient of thermal conductivity and the heat from the electrical resistance heater in the syringe barrel is conducted thermally into the needle to maintain the needle above 230.degree. F. The heat enables the thermoplastic material to flow through the needle. A manual plunger is provided in the syringe barrel for ejecting the flowable material.
Suitable materials having a high coefficient of thermal conductivity for use in the heater body, hub and needle are very costly. Herskovitz et al. suggests the use of silver or copper. It is an object of the present invention to provide an electrically heated device for dispensing endodontic materials without resorting to extensive use of these high cost materials. Thus, advantageously, the present invention provides disposable cartridges which comprise integral heating elements for maintaining the extruded material in a flowable condition until it exits from the end of a thin elongated hollow probe.